1. Technical Field
The present invention relates to a valve control device of a vacuum valve of which opening degree is adjustable.
2. Background Art
In a vacuum processing device such as a CVD device, an inner chamber pressure normally varies according to a processing process stage (e.g., during, before, or after a process). Thus, in such a vacuum processing device, a vacuum valve of which opening degree is adjustable is provided between a vacuum chamber and a vacuum pump, thereby performing pressure adjustment. A valve described in Patent Literature 1 (Japanese Patent No. 4630994) has been known as an example of such a valve.
In general, this vacuum valve performs such control that a pressure deviation between a desired set pressure and a current pressure is calculated for controlling the inner chamber pressure to the set pressure and a feedback of the pressure deviation is added to a valve opening degree.
However, when pressure deviation feedback is performed with the same parameter, a pressure adjustment time varies among different pressure control regions, leading to a problem that pressure adjustment performance is not stabilized.